code:

   class Foo {
        int id;
        String name;
   }


   // Bad, can't unit test processing logic
   static Foo getAndProcessFoo(int fooId) {
        Foo foo = db.getFoo(fooId);
        foo.name = "butts";
       return foo;
   }


   // Better, can easily unit test static 'processFoo' method, good enough for simple stuff
   static Foo processFoo(Foo foo) {
        foo.name = "butts";
        return foo;
   }

   Foo getAndProcessFoo(int fooId) {
        return Class.processFoo(database.getFoo(fooId));
    }

  // Best, can swap out database/fooprocessor for integration testing and extension, and can test each as units. 
  interface Database {
     Foo getFoo(int);
  }

 interface FooProcessor {
    Foo process(Foo);
 }

  static <D extends Database, F extends FooProcessor> getAndProcessFoo(D db, F fp, int fooId) {
     return fp.process((db.getFoo(fooId)))
  }